Treatment of textile fabrics with polyvinyl compound



Aug. 8, 1950 H. EWING 2,517,646

TREATMENT OF TEXTILE FABRICS WITH POLYVINYL couvouun Filed May 6. 1947Inilentor MEW/M;

By M r A Horney Patented Aug. 8, 1950 TREATMENT OF TEXTILE FABRICS WITHPOLYVINYL COMPO UND Henry Ewing, Spondon, near Derby, England, as-

signor to Celanese Corporation of America, a

corporation of Delaware Application May 6,1941, Serial No..'l46,384 InGreat Britain May an, 1946 8 Claims. (01. 117-161) 1 This inventionrelates to the treatment of woven, knitted and netted textile fabrics toreduce their liability to slipping, fraying, laddering or the like.

In accordance with the invention there is applied to woven, knitted ornetted textile fabrics a composition comprising an acetone-insolublepolyvinyl chloride or a co-polymer of vinyl chloride and vinyl acetatewith a vinyl chloride content of 80-95 and preferably also a plasticiserfor the polyvinyl compound, in amount insuihcient to close theinterstices of the fabric. The expression polyvinyl composition" isemployed hereinafter to denote compositions comprising the polyvinylcompound, whether or not they also comprise a plasticiser.

The amount of the polyvinyl composition ap plied to the fabric ispreferably small, especially between about 0.25 and 7.0% of the weightof the fabric.

In the preferred method of putting the invention into practice thefabric is impregnated with a dope comprising the polyvinyl compound andpreferably a plasticiser dissolved in a suitable liquid solvent medium,and the solvent medium is then removed by evaporation, leaving thepolyvinyl composition 9n the fabric.

The choice of a suitable solvent medium is a matter of importance. Itmust. of course, be capable of dissolving the polyvinyl compound and theplasticiser if one is employed. (Either a true solution or a colloidaldispersion of the polyvinyl compound and/or the plasticiser may beformed, and the term solution is used hereinafter to include both kindsof composition.) It must not exert any undesired action on the materialof which the fabric is composed. For example it must not dissolve thematerial. Moreover, I have found that a very much better product resultsif the solvent medium is one which on evaporation is capable ofdepositing the polyvinyl compound in the form of a film.

Examples of liquids which fulfil this last condition are certainaliphatic ketones, especially methyl ethyl ketone; certain aliphaticdihalides, in particular propylene dichloride; and dioxane andtetrahydrofurane. Since methyl ethyl ketone, propylene dichloride,dioxane' and tetrahydrofurane are substantially without action oncellulose, fabrics made of cellulose yarns, e. g. viscose orcuprammonium cellulose yarns or yarns made by saponifying stretchedcellulose acetate yarns, may advantageously be treated with a solutionof the polyvinyl compound and a plasticlser in one of these solvents.Solutions 2 of the polyvinyl compound and plasticiserin propylenedichloride can also be used for the treatment of fabrics made of yarnshaving a basis of an organic derivative of cellulose, for

example cellulose acetate. Methyl ethyl ketone,

dioxane and tetrahydrofurane however, are solvents or strong swellingagents for cellulose acetate and are not suitable by themselves fortreating fabrics containing cellulose acetate. I have found thatmixtures of these solvents, and especially of methyl ethyl ketone, withaliphatic ketones containing at least 5 carbon atoms, for exampledi-isopropyl ketone, and especially methyl alkyl ketones such as methyliso-butyl ketone and methyl n-amyl ketone, can be used verysatisfactorily. These higher aliphatic kctones can, if desired, beemployed alone, but this is less satisfactory, since, except from verydilute solutions, they tend to deposit the polyvinyl compound in acontinuous or granularform rather than as a film. Propylene dichloride,on the other hand, can be used satisfactorily either alone or inadmixture with methyl ethyl ketone. Examples of suitable mixtures whichmay be used at temperatures of about 20 C. are: 70 parts of methyl ethylketone with 30 parts of methyl isobutyl ketone .or methyl n-amyl ketone:75 parts of methyl ethyl ketone with 25 parts of di-isopropyl ketone;parts of methyl ethyl ketone with 45 parts of propylene dichloride; aswell as similar mixtures containing a lower proportion of methyl ethylketone, e. g. down to about 20% in the case of the mixtures with11181181 ketones. Mixtures of methyl ethyl hexane with hydrocarbons,especially mononuclear aromatic hydrocarbons, instead of with the higherketones or with propylene dichloride, can also be used, though lessadvantageously.

Examples of such mixtures are parts or less of methyl ethyl ketone with40 parts or more of benzene or a xylene. In all cases the parts givenare by volume.

The concentration of the polyvinyl compound in the solvent medium ispreferably between about 1% and 12%. The precise concentration which hasno deleterious effect upon the material of which the fabric is composedand does not impart undesirable properties to the fabric. Theplasticisers which it is preferred to employ are organic phosphates, e.g. tricresyl phosphate and other triaryl phosphates and tributylphosphate; phthalate plasticisers, e. g. dibutyl phthalate, dioctylphthalate and dilauryl phthalate; dibutyl and dioctyl sebacate, dibutyladipate, tributyl citrate, tetra-hydrofuryl oleate and methylcyclohexanol oxalate. The amount of the plasticiser may be between 25%and 200% of the weight of the polyvinyl compound, but is preferablybetween about 50% and 140%, especially about 100%.

If desired the polyvinyl composition may also contain a heat orlight-stabiliser, e. g. lead stearate or other heavy metal salt,diphenyl thiourea, alpha-phenyl indole or adipic acid dihydrazide.

As already indicated, the polyvinyl compositions can be applied withgood results to fabrics made of very different materials. For example,they can be applied to fabrics having a basis of natural cellulose, e.g. cotton, or of a regenerated cellulose staple fibre. The treatment is,however, of particular advantage in connection with fabrics made ofcontinuous filaments, either of regenerated cellulose, e. g. viscose andmore especially regenerated cellulose filaments made by first stretchingand then saponifying cellulose acetate filaments, or of an ester orether of cellulose, in particular cellulose acetate or cellulosepropionate. Fabrics comprising continuous filaments or staple fibres ofpurely synthetic polymeric materials, e. g. polyamides of the nylon typeor polyurethanes, may also be treated in accordance with the invention.

Not only should the amount of the polyvinyl composition applied to thefabric be small, but for most purposes it is important that thecomposition should be evenly distributed on the fabric, While it ispossible to apply the composition in pre-determined amount by passingthe fabric through the dope and removing excess dope by means of one ormore doctor blades, the following device has been found to beparticularly effective, especially for the treatment of woven fabrics.

The device comprises means for wetting the fabric with the dope incombination with a number of fixed bars, e. g. straight cylindricalbars, parallel to one another and spaced in such a way that a fabricpassed successively between each pair of adjacent bars and held undertension presses against each bar. The effect of the bars is todistribute the dope evenly over and throughout the fabric and to removedope in excess of the amount desired on the fabric. The fabric may bewetted with the dope in any convenient way, for example by passing thefabric through a bath of the dope immediately before passing it throughthe series of bars as described.

One such device comprises a free-running or driven roller immersed in abath of the dope and, situated above the rollers, a series of fixed,cylindrical, steel bars each parallel to the roller. There may, forexample, be 4, 6 or 8 of these bars, and preferably at least one of themis situated below the level of the surface of the dope, while themajority are above the surface level. For example the device maycomprise a roller and one bar below the surface level of the dope andfour or five bars above the surface level. Preferably the axes of thebars lie in a single plane, which may either be vertical or inclined atan angle to the vertical.

tached to the sides of the vessel l.

The accompanying drawing is a sectional view of a device of this kind,comprising a vessel I for the dope to be applied to the fabric and twovertical members 2 mounted on brackets 3 at- A free-running roller 4 ismounted in bearings near the lower end of the members 2 and above it,but below the level to which the vessel I can be filled with liquid, ismounted a fixed cylindrical steel bar 5. Above this bar, and equallyspaced therefrom and from each other, are fixed further similar bars 6.

In operation, the fabric to be treated is caused to travel through thebath and under the roller 4 and then in a zigzag manner between adjacentbars 5 and 6. For example, it may be drawn through the device by a pairof nip rollers (not shown in the drawing). By adjusting the tension onthe fabric, and thus the pressure of the fabric against the bars, it ispossible very closely to control the amount of dope remaining on thefabric. It has been found that this device has the further advantage ofeliminating troubles due to bubbles in the dope and of distributing thepolyvinyl composition evenly over the fabric even when the concentrationof the polyvinyl composition in the dope is high, e. g. up to 200grammes of the composition per litre of dope.

For applying to knitted or netted fabrics the relatively smallquantities of liquid required for the treatment above described, it ispreferred to employ a padding device, for example a device in which thefabric is fed between two rollers together with and above an endlessthick woollen blanket, the lower bight of which passes through the bathcontaining the dope. The amount of the dope remaining on the fabric maybe controlled by varying the pressure exerted by the rollers on thefabric and blanket. If desired, 2. padding device can also be used forapplying the dope to woven fabrics.

The removal of the liquid component or components of the dope from theimpregnated fabric b evaporation may, for example, be effected bypassing the impregnated fabric through a chamber through which passes acurrent of heated air or other gas. The air or other gas, after passingthrough the chamber, may be freed from the vapours of the liquidcomponent or components of the dope, e. g. by condensation or byadsorption on charcoal, activated alumina or silica gel, and may then berecirculated through the chamber. The separated liquid or liquids may beemployed in the production of further quantities of dope.

It has been found that fabrics which have been subjected to thetreatment described can be dyed in an even and satisfactory manner bythe same general methods and using the same dyestuffs as if they had notbeen so treated. For example cotton fabrics and fabrics of regeneratedcellulose may be dyed by the standard methods with direct cotton dyes,for example Chlorantine Fast Blue 4GL or Durazol Yellow 6G; celluloseacetate fabrics can be dyed by the standard methods using aqueousdispersions of substantially waterinsoluble dyes. Moreover, a pleasingeffect can be produced by incorporating a dyestuff in the polyvinylcomposition; thus the composition may be applied in the form of a dopecontaining the dyestufi, preferably a water-insoluble dye soluble in thedope or a coloured pigment, for example in'amount 0.0l-l% by weight ofthe polyvinyl compound. If a high degree of covering power is required,the dope may also contain a white filler, e. g. titanium dioxide, zincoxide, or another '5 white pigment, for example in amount up to 10% ofthe weight of the polyvinyl compound.

The new process is of value in the treatment of woven, knitted andnetted fabrics of various types and of textile articles made therefrom.For example, it is of great value in the treatment of hosiery,especially hosiery comprising regenerated cellulose yarns made bystretching and then saponifying cellulose acetate yarns, in order toreduce their liability to ladder.

The invention is illustrated by the following example:

Example Sufflcient methyl ethyl ketone is added to anemulsion-polymerised, spray-dried polyvinyl chloride to form agelatinous mass, which is then finely broken up. Tricresyl phosphate isadded in amount equal to the weight of the polyvinyl chloride andfurther methyl ethyl ketone is added with agitation until adopeconsisting of a solution of the polyvinyl chloride and tricresylphosphatev is obtained, the concentration of polyvinyl chloride in thedope being about The vessel 1 of the device illustrated in the drawingsis filled with the dope, which is kept at a temperature of 20 C. r

A light-weight woven fabric of regenerated cellulose (made by weavingyarns produced by stretching and saponifying cellulose acetate yarns) isdrawn through the dope under the roller ,4 and in a zigzag path betweenthe series of bars 5, 5. The tension on the fabric is such that thefabric retains 25-35% of its weight of the dope.

The fabric carrying the dope is then passed through a drying chamber inwhich it meets a current of heated air whereby the methyl ethyl ketoneis substantially completely evaporated.

When a cellulose acetate fabric is treated the amount of methyl ethylketone used is reduced by 30%; the solution so obtained is diluted withmethyl isobutyl ketone or methyl n-amyl ketone in amount suflicient tobring it to the same concentration of polyvinyl chloride as before.

The treated fabrics have a greater resistance to slipping than untreatedsimilar fabrics and can be evenly dyedthe regenerated cellulose fabricwith direct cotton-dyes and the cellulose acetate fabric with an aqueousdispersion of a water-insoluble dye.

If, instead of using the device described in the drawing for applyingthe dope to the fabric, the dope is applied by a padding method, it maycontain 7.5 parts each of the polyvinyl chloride and tricresyl phosphatein 100 parts of the ketone or mixture of ketones used. ,Such a solutioni also used in the treatment of knitted fabrics and,

articles by the padding method.

Having described my invention, what I desire to secure by Letter Patientis:

1. Process for the treatment of woven, knitted and netted fabricscomprising continuous fila- 8 fabric being insufficient to close theinterstices of the fabric.

2. Process according to claim 1, wherein the amount of plasticizer inthe composition is 25%-200% of the weight of the polyvinyl compound.

3. Process for the treatment of woven, knitted and netted fabricscomprising continuous filament yarns of organic derivatives ofcellulose, which comprises depositing on the fabric from a solution of3%9% concentration a composition comprising a polyvinyl compoundselected from the group which consists of copolymers of vinyl chlorideand vinyl acetate having a vinyl chloride content of 80 %-95% andacetone-insoluble polyvinyl chloride, dissolved in a mixture consistingessentially of 20 to 75% of methyl ethyl ketone the remainder being amethyl alkyl ketone containing at least 5 carbon atoms, the amount ofthe said composition deposited on the fabric being insuflicient to closethe interstices of the fabric, and between 0.25% and 7% of the weight ofthe fabric.

4. Process for the treatment of woven, knitted and netted fabricscomprising continuous filaments yarns of organic derivatives ofcellulose, which comprises depositing on the fabric from r a solution of3%-9% concentration a composiment yarns of organic derivatives ofcellulose,

tion comprising a polyvinyl compound and a plasticizer therefore, saidpolyvinyl compound being selected from the group which consists ofcopolymers of vinyl chloride and vinyl acetate having a vinyl chloridecontent of and acetone-insoluble polyvinyl chloride, dissolved in amixture consisting essentially of 20 to 75% of methyl ethyl ketone theremainder being a methyl alkyl ketone containing at least 5 carbonatoms, the amount of the said composition deposited on the fabric beinginsufficient to close the interstices of the fabric.

5. Process for the treatment of woven, knitted and netted fabricscomprising continuous filament yarns of organic derivatives ofcellulose, which comprises depositing on the fabric from a solution of3%9% concentration a composition comprising a polyvinyl compound and aplasticizer therefore, said polyvinyl compound being selected from thegroup which consists of copolymers of vinyl chloride and vinyl'acetatehaving a vinyl chloride content of 80%-95% and acetoneinsolublepolyvinyl chloride, dissolved in a mixture consisting essentially of 20to 75% of methyl ethyl ketone the remainder being a methyl alkyl ketonecontaining at least 5 carbon atoms, the amount of the said compositiondeposited on the fabric being insufiicient to close the interstices ofthe fabric, and between 0.25% and 7% of the weight of the fabric.

6. Process for the treatment of woven, knitted and netted fabricscomprising continuous filament yarns of organic derivatives ofcellulose, which comprises depositing on the fabric at a temperature of15 to- 30 C. from a solution of 3%-9% concentration a compositioncomprising a polyvinyl compound selected from the group which consist ofcopolymers of vinyl chloride and vinyl acetate having a vinyl chloridecontent of 80%-95% and acetone-insoluble polyvinyl chloride, dissolvedin a mixture consisting essentially of 20 to 75% of methyl ethyl ketonethe remainder being a methyl alkyl ketone containing at least 5 carbonatoms, the amount of the said composition deposited on the fabric beinginsufficient to close the interstices of the fabric,

7 and between 0.25% and 7% of the weight of the fabric.

'1. Process for the treatment of woven, knitted and netted fabricscomprising continuous filament yarns of organic derivatives ofcellulose, which comprises depositing on the fabric at a temperature of15 to 30 C. from a solution of 3%-9% concentration a polyvinyl compoundand a plasticizer therefore, said polyvinyl compound being selected fromthe group which consists of copolymers of vinyl chloride and vinylacetate having a vinyl chloride content of 80 %-95% andacetone-insoluble polyvinyl chloride, dissolved in a mixture consistingessentially of 20 to 75% of methyl ethyl ketone the remainder being amethyl alkyl ketone containing at least 5 carbon atoms, the amount ofthe said composition deposited on the fabric being insufficient to closethe interstices of the fabric, and between 0.25% and 7% of the weight ofthe fabric.

8. Process for the treatment of woven fabrics made from continuousfilament yarns of an organic derivative of cellulose, which comprisespassing the fabric through a %-9% solution of a composition comprising apolyvinyl compound and a plasticizer therefore, said polyvinyl compoundbeing selected from the group which consists of copolymers of vinylchloride and vinyl acetate having a vinyl chloride content of 80%-95%and acetone-insoluble polyvinyl chloride, in a solvent medium comprisingmethyl ethyl ketone in admixture with a methyl alkyl ketone containingat least 5 carbon atoms, then subjecting the fabric to repeatedsubstantially uniform pressure and friction on its two sides alternatelyuntil the solution remaining on the fabric contains an amount of thecomposition insuflicient to close the interstices of the fabric andbetween 0.25% and 7% of the weight of the fabric, and subsequentlyevaporating the solvent medium.

HENRY EWING.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,015,103 Dreyfus Sept. 24, 19352,057,671 Dreyfus Oct. 20, 1936 2,066,079 Shoub Dec. 29, 1936 2,176,053Billing Oct. 17, 1939 2,230,358 Mason Feb. 4, 1941 2,245,708 Patton June17, 1941 FOREIGN PATENTS Number Country Date 397,711 Great Britain Aug.31, 1933 Certificate of Correction Patent No. 2,517,646

August 8, 1950 HENRY EWING It is hereby certified that error appears inthe printed specification of the above numbered patent requiringcorrection as follows:

Column 7, line 8, after the word concentration insert a compositioncomprising;

and that the said Letters Patent should be read as corrected above, sothat the same may conform to the record of the case in the PatentOflice.

Signed and sealed this 21st day of November, A. D. 1950.

[SEAL] THOMAS F. MURPHY,

Assistant C'ommissz'oner of Patents.

1. PROCESS FOR THE TREATMENT OF WOVEN, KNITTED AND NETTED FABRICSCOMPRISING CONTINUOUS FILAMENT YARNS OF ORGANIC DERIVATIVES OFCELLULOSE, WHICH COMPRISES DEPOSITING ON THE FABRIC FROM A SOLUTION OF3%-9% CONCENTRATION A COMPOSITION COMPRISING A POLYVINYL COMPOUNDSELECTED FROM THE GROUP WHICH CONSISTS OF COPOLYMERS OF VINYL CHLORIDEAND VINYL ACETATE HAVING A VINYL CHLORIDE CONTENT OF 80%-95% ANDACETONE-INSOLUBLE